Thanks for the clarification. I'll check with tech support right now, but I *think* that DirectRT doesn't have access to DTR/RTS/the other flow control pins.

I don't suppose your machine has a parallel port, or that you could add one with an expansion card? They're about $10 these days.

Be careful skipping those resistors. Though RS232 is supposed to be short-tolerant, it'd be embarrassing to trash an output stage for want of an $0.01 part.